In general, optical chemical sensing technology includes the use of an optical excitation source such as light to excite an optical chemical sensor. In response to the excitation, the optical chemical sensor emits luminescence or absorbs light which is measured by a detector. If the optical chemical sensor is in fluidic contact with the liquid media in a cell culture, the pH of the liquid media or the dissolved oxygen (DO) in the liquid media can be determined by analysis of the luminescence emitted from the sensor or of the amount of light absorbed by the sensor. Changes in either the luminescence emitted, or in the amount of light absorbed can be used to monitor in real time changes in pH or changes in the concentration of an analyte.
The use of optical chemical sensors in bioprocessing provides a means for automating the monitoring, adjusting, and optimizing of conditions within a bioreactor, thereby accelerating pharmaceutical manufacturing processes, such as, e.g., processes that include growing cells for production of therapeutic proteins, monoclonal antibodies, vaccines, and the like.
Biological, chemical, and/or pharmaceutical manufacturing processes traditionally have been carried out in stainless steel or glass vessels. Increasingly, however, single-use or flexible-walled bags and tubing systems have been used for bioprocessing.
As is well known by those of skill in the art, many problems are encountered in process of attaching various types of sensor assemblies to polymeric or flexible plastic materials, or in securing a sensor assembly to a film, flexible bags, and flexible tubing,
A conventional optical sensor and its housings for flexible or semi-rigid containers (such as disposable bags or plastic tubing) require an attachment such as a “window” or a “receiver” that is attached to the flexible wall of the container. One disadvantage of this commercially available design is that it requires an additional assembly and components to attach the sensor-housing assembly to the flexible wall or semi-rigid wall. Another disadvantage of current designs is that the design also requires a penetration through the wall of the flexible container or tubing in which the “window” or sensor and its housing “receiver” is attached. The penetration can lead to leakage of liquids in the container or tubing or contamination of the liquids. Contamination or potential contamination is an ongoing problem of critical concern in pharmaceutical or medical applications. Another disadvantage of currently available optical sensor assemblies for use in flexible wall systems is that, following the attachment of the sensor and its housing to a flexible bag or tubing, the position of the sensor and its housing assembly cannot be moved.